Union Pacific 3985 or UP 3985 is a four-cylinder simple articulated 4-6-6-4

4-6-6-4

In Whyte notation, a 4-6-6-4 is a railroad steam locomotive that has four leading wheels followed by six coupled driving wheels, a second set of six driving wheels and four trailing wheels.Other equivalent classifications are:...

 Challenger-type steam locomotive

Steam locomotive

A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...

 owned by Union Pacific Railroad

Union Pacific Railroad

The Union Pacific Railroad , headquartered in Omaha, Nebraska, is the largest railroad network in the United States. James R. Young is president, CEO and Chairman....

. The UP 3985 locomotive was built in 1943 by the American Locomotive Company of Schenectady, New York

New York

New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

. It is currently the largest operational steam locomotive in the world.

Design

Designed by UP chief mechanical engineer Otto Jabelmann in 1941, UP 3985 was part of the second order of this second version of the Challenger. The design drew on recent experience with the enormous 4-8-8-4

4-8-8-4

In the Whyte notation for the classification of steam locomotives by wheel arrangement, a 4-8-8-4 is a locomotive with a four-wheel leading truck, two sets of eight driving wheels, and a four-wheel trailing truck.Other equivalent classifications are:...

 Big Boy

Union Pacific Big Boy

Big Boy was the name of the Union Pacific Railroad's 4000-class 4-8-8-4 articulated steam locomotives, built between 1941 and 1944 by American Locomotive Company...

 locomotives, and resulted in a locomotive in working order weighing some 317 short ton

Short ton

The short ton is a unit of mass equal to . In the United States it is often called simply ton without distinguishing it from the metric ton or the long ton ; rather, the other two are specifically noted. There are, however, some U.S...

s accompanied by a tender weighing 174 short tons when 2/3 loaded. Calculated tractive effort is 97,350 lbf. The Challenger class was intended to speed up freight operations on the 0.82% grades across Wyoming; the 1.14% Wasatch climb east from Ogden was to be conquered by the Big Boys without helpers. The Challengers and Big Boys arrived on the scene just as traffic was surging in preparation for American participation in World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

.

Service and Restoration

UP 3985 operated in its last "regular" train service in 1957. The locomotive was retired about 1962 and after many years of storage in a roundhouse at Cheyenne

Cheyenne, Wyoming

Cheyenne is the capital and most populous city of the U.S. state of Wyoming and the county seat of Laramie County. It is the principal city of the Cheyenne, Wyoming, Metropolitan Statistical Area which encompasses all of Laramie County. The population is 59,466 at the 2010 census. Cheyenne is the...

, Wyoming

Wyoming

Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...

, UP 3985 was placed on an outdoor display beside the Cheyenne depot in 1975. Beginning in 1979 a group of Union Pacific employee-volunteers started work on restoring the locomotive, and it was returned to operational condition in 1981. Originally a coal-burner, to prevent lineside grass fires it was successfully converted to oil firing in 1990. Stationed at Cheyenne with other equipment in the UP's heritage collection, it is currently used for excursion trains and occasionally mainline freight on ferry moves. It was in the maintenance shop at Cheyenne in 2007 and underwent necessary repairs for service in 2008. It is now back up and running. It is one of only two of the original 105 Union Pacific "Challenger" types in existence, the other being UP 3977 on static display in North Platte, Nebraska

North Platte, Nebraska

North Platte is a city in and the county seat of Lincoln County, Nebraska, United States. It is located in the southwestern part of the state, along Interstate 80, at the confluence of the North and South Platte Rivers forming the Platte River...

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External links

• Union Pacific Steam Shop Information on locomotives and excursion schedules.
• UP 3985 Challenger, Steam Locomotive - photos and additional information